1. Field of the Invention
The present invention relates to a heating device and a semiconductor manufacturing apparatus,
2. Description of the Related Art
To fabricate a semiconductor thin film using source gas, such as silane gas, by thermal CVD, plasma CVD, or the like, a semiconductor manufacturing apparatus employs a heating device for heating a wafer. A known type of heating device includes a disk-shaped ceramic base that has a wafer-receiving surface, a resistance heating element disposed inside or on the surface of the ceramic base, and a hollow shaft attached to the surface opposite to the wafer receiving surface of the ceramic base. Various methods for making the temperature of the wafer-receiving surface of the heating device uniform are known. For example, in the case where a coil-spring-shaped resistance heating element (winding element is buried in the ceramic base, the amount of heat generated per unit area of the wafer-receiving surface can be increased by increasing the number of turns of winding or the diameter of winding or by reducing the diameter of the wire. The amount of heat generated per unit area of the wafer-receiving surface (density of heating) can be reduced by reducing the number of turns of winding or the diameter of winding or by increasing the diameter of the wire.